(1) Field of the Invention
The present invention relates to a grain-milling machine, and more particularly to a vertical type grain-milling machine in which grains are supplied from one side of a vertical bran removing cylinder for causing the grains to move up or move down while the grains are being subjected to milling action in the bran removing cylinder and the grains are discharged from the other side of the bran removing cylinder.
(2) Description of the Related Art
A conventional vertical type grain-milling machine of the kind to which the present invention relates has been disclosed in Japanese Patent Application Kokai (Laid Open) No. 146137/1991 in which the inventors are the same as those in the present application. By making reference to FIG. 1, such a conventional grain-milling machine is first explained to assist the understanding of the present invention.
As seen in FIG. 1, a vertical type grain-milling machine 100 is arranged such that, within a vertical perforated bran removing cylinder 101, a vertical shaft 102 carries a screw roll 103 and an abrasive milling roll 104 together with the screw roll 103 being disposed at a lower position and the abrasive milling roll 104 at an upper position of the vertical shaft 102. Grains are supplied to the screw roll 103 via a feeding chute 105 by a screw conveyor 106 and are elevated, by the rotating action of the screw roll 103, to a milling chamber formed between the bran removing cylinder 101 and the milling roll 104. Then, the grains are subjected to the milling action produced by the rotation of the abrasive milling roll 104, and the grains thus processed are discharged externally of the machine from an outlet 109 against the resistance generated by a resisting plate 110 via an outlet chute 111. The bran which has been removed from the grains due to the milling action within the bran removing cylinder 101 is drawn by a suction fan 115 and discharged externally of the machine through a number of perforations provided in the bran removing cylinder 101.
However, there have existed certain drawbacks in the conventional vertical type grain-milling machine described above. Specifically, although the bran is sufficiently discharged at that side of a surface 101a of the bran removing cylinder 101 which is close to the suction duct 116 connected to the suction fan 115, the bran discharging action at that side of a surface 101b of the bran removing cylinder 101 which is disposed opposite to the suction duct 116 is insufficient simply because the sucking force at that side is weaker. This results in the deterioration of bran removal from grains and in the clogging of the perforations of the bran removing cylinder 101.